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A mixed phase-field model for fracture propagation behavior in Gulong shale with complex wavy bedding

Journal of Rock Mechanics and Geotechnical Engineering 2025年

作者： Siwei Meng Zihan Zhang Wenlong Xu Hao Yu Hengan Wu He Liu PetroChina Research Institute of Petroleum Exploration & Development Beijing 100083 China National Key Laboratory of Continental Shale Oil Daqing 163002 China CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern Mechanics University of Science and Technology of China Hefei 230027 China

Shale reservoirs have abundant bedding structures, which deeply alter the mechanical properties of rocks, and thus affect the reservoir stimulation performance. Previous research mostly focuses on the effects of parallel bedding on fracture propagation, while the mechanical properties and mechanisms of fracture propagation remain unclear for rocks with complex wavy bedding (e.g. China’s continental-origin Gulong shale). Herein, a mixed phase-field fracture model of the wavy-bedding shale was applied, based on the local tension-compression decomposition phase field method (PFM) and geometric structure generation algorithm for the bedding with controllable morphological features. The parametric analysis of fracture propagation behaviors in the case of abundant complex bedding structures showed that with wavy bedding, the vertical fracture propagation rate is far higher than the horizontal propagation rate. Moreover, the development of branch fractures is suppressed during the fracturing process of the wavy-bedding sample, and the stimulated volume is limited, which is different from the characteristic of parallel bedding that promotes horizontal fracture initiation and propagation. The results showed that larger amplitudes, higher frequencies, higher inclination angles, and larger strengths of wavy bedding all promote the formation of vertical penetrating fractures and suppress the growth of branch fractures. Under such circumstances, it is hard to create a well-connected fracture network after fracturing. This research may provide a theoretical basis for understanding fracture behaviors in rocks with such complex wavy bedding.

关键词： Continental shale Complex wavy bedding Cracking behavior Phase field method Branch fractures

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wBoc-phenylalanine Grafted Poly(3,4-propylenedioxythiophene) Film for Electrochemically Chiral Recognition of 3,4-Dihydroxyphenylalanine Enantiomers

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高分子科学（英文版） 2019年第5期中插2,451-461页

作者： Jun-Long Niu Ke-Ke Chai Mei-Xing Zeng Tian-Tian Wang Chun-Yan Zhang Shuai Chen Jing-Kun Xu Xue-Min Duan Jiangxi Provincial Key Laboratory of Drug Design and Evaluation School of Pharmacy Jiangxi Science & Technology Normal University Nanchang 330013 China Jiangxi Provincial Key Laboratory of Drug Design and Evaluation School of Pharmacy Jiangxi Science & Technology Normal University Nanchang 330013 China School of Chemistry and Molecular Engineering Qingdao University of Science and Technology Qingdao 266042 China

To prepare chiral monomer with single chiral center and higher stereospecificity, a pair of amino-functionalized chiral 3,4-propylenedioxythiophene (ProDOT) derivatives, chiral (3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin-3-yl)methyl 2-[(tert-butoxycarbonyl) amino]-3-phenylpropanoate (ProDOT-Boc-Phe), were synthesized. Chiral poly[(3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin-3-yl)methyl 2-[(tert-butoxycarbonyl)amino]-3-phenylpropanoate] (PProDOT-Boc-Phe) modified electrodes were synthesized via potentiostatic polymerization of chiral ProDOT-Boc-Phe. Chiral PProDOT-Boc-Phe films displayed good reversible redox activities. The enantio-selective recognition between chiral PProDOT-Boc-Phe modified glassy carbon electrodes and DOPA enantiomers was achieved by different electrochemical technologies, including cyclic voltammetry (CV), square wave voltammetry (SWV), and differential pulse voltammetry (DPV). (D)-PProDOT-Boc-Phe and (L)-PProDOT-Boc-Phe showed higher peak current responses toward L-DOPA and D-DOPA, respectively.

关键词： Chiral conducting polymer Amino acids Chiral sensors 3 4-Dihydroxyphenylalanine Electrochemistry

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PM10 formation behaviors from combustion of municipal solid waste and refuse-derived fuel: Insight into volatile-char interactions

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Fuel 2025年 399卷

作者： Liu, Tianyu Wen, Chang Wang, Dapeng Liu, Fangqi Huang, Lei Yu, Xin Yu, Dunxi State Key Laboratory of Coal Combustion School of Energy and Power Engineering Huazhong University of Science and Technology Wuhan430074 China Department of New Energy Science and Engineering School of Energy and Power Engineering Huazhong University of Science and Technology Wuhan430074 China China-EU Institute for Clean and Renewable Energy Huazhong University of Science and Technology Wuhan430074 China Central Southern China Electric Power Design Institute Co. Ltd. of China Power Engineering Consulting Group Wuhan430071 China

This study elucidates the complex mechanisms of volatile-char interactions governing PM10 (particulate matter with an aerodynamic diameter ≤ 10 µm) formation during the combustion of municipal solid waste (MSW) and refuse-derived fuel (RDF). Using an innovative two-stage quartz reactor coupled with a drop tube furnace system (700–1000 ℃), three primary mechanisms influencing PM10 formation were identified: AAEMs (alkali and alkaline earth metals) redistribution, char structural modification, and char reactivity alteration. The findings reveal that H radicals in volatiles facilitate AAEMs (primarily Na and K) displacement from the char carbon matrix, enhancing PM0.2 formation through homogeneous nucleation during volatile combustion. Notably, MSW exhibits a less pronounced increase in PM0.2 yield compared to RDF due to higher initial AAEMs concentration in volatiles suppressing further AAEMs volatilization from char. During char combustion, volatile-char interactions significantly increase macropore volume in both fuels, intensifying char fragmentation and PM2-10 emissions. However, the depletion of small-ring aromatics and oxygen-containing functional groups reduces char reactivity, particularly in RDF, resulting in a smaller increase in PM2-10 emissions compared to MSW. Overall, the decomposition of oxygen-containing structures, changes in aromatic structures, and AAEMs redistribution collectively govern the distinct PM10 formation behaviors observed during volatile-char interactions, providing crucial insights for emission control strategies. © 2025 Elsevier Ltd

关键词： Emission control

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Central-Upwind Scheme for the Phase-Transition Traffic Flow Model

arXiv

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arXiv 2025年

作者： Chu, Shaoshuai Kurganov, Alexander Mohammadian, Saeed Zheng, Zuduo Department of Mathematics RWTH Aachen University Aachen52056 Germany Department of Mathematics Shenzhen International Center for Mathematics Southern University of Science and Technology Shenzhen518055 China Department of Mathematics Shenzhen International Center for Mathematics Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and Technology Shenzhen518055 China School of Civil Engineering University of Queensland BrisbaneQLD4072 Australia

Phase-transition models are an important family of non-equilibrium continuum traffic flow models, offering properties like replicating complex traffic phenomena, maintaining anisotropy, and promising potentials for accommodating automated vehicles. However, their complex mathematical characteristics such as discontinuous solution domains, pose numerical challenges and limit their exploration in traffic flow theory. This paper focuses on developing a robust and accurate numerical method for phase-transition traffic flow models: We propose a second-order semi-discrete central-upwind scheme specifically designed for discontinuous phase-transition models. This novel scheme incorporates the projection onto appropriate flow domains, ensuring enhanced handling of discontinuities and maintaining physical consistency and accuracy. We demonstrate the efficacy of the proposed scheme through extensive and challenging numerical tests, showcasing their potential to facilitate further research and application in phase-transition traffic flow modeling. The ability of phase-transition models to embed the "time-gap"—a crucial element in automated traffic control—as a conserved variable aligns seamlessly with the control logic of automated vehicles, presenting significant potential for future applications, and the proposed numerical scheme now substantially facilitates exploring such potentials. © 2025, CC BY.

关键词： Finite volume method

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A New Locally Divergence-Free Path-Conservative Central-Upwind Scheme for Ideal and Shallow Water Magnetohydrodynamics

arXiv

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arXiv 2022年

作者： Chertock, Alina Kurganov, Alexander Redle, Michael Wu, Kailiang Department of Mathematics Center for Research in Scientific Computing North Carolina State University RaleighNC27695 United States Department of Mathematics SUSTech International Center for Mathematics Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and Technology Shenzhen518055 China Department of Mathematics North Carolina State University RaleighNC27695 United States Shenzhen518055 China

We develop a new second-order unstaggered path-conservative central-upwind (PCCU) scheme for ideal and shallow water magnetohydrodynamics (MHD) equations. The new scheme possesses several important properties: it locally preserves the divergence-free constraint, it does not rely on any (approximate) Riemann problem solver, and it robustly produces high-resolution and non-oscillatory results. The derivation of the scheme is based on the Godunov-Powell nonconservative modifications of the studied MHD systems. The local divergence-free property is enforced by augmenting the modified systems with the evolution equations for the corresponding derivatives of the magnetic field components. These derivatives are then used to design a special piecewise linear reconstruction of the magnetic field, which guarantees a non-oscillatory nature of the resulting scheme. In addition, the proposed PCCU discretization accounts for the jump of the nonconservative product terms across cell interfaces, thereby ensuring stability. We test the proposed PCCU scheme on several benchmarks for both ideal and shallow water MHD systems. The obtained numerical results illustrate the performance of the new scheme, its robustness, and its ability not only to achieve high resolution, but also preserve the positivity of computed quantities such as density, pressure, and water depth. © 2022, CC BY.

关键词： Magnetohydrodynamics

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The Power Control Method of Data Center Based on Cloud- Edge Collaboration

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Journal of Physics: Conference Series 2021年第1期1754卷

作者： Junjie Zhao Yucheng Hou Liu Liu Feng Xie Xiang Mao Pan Luo Jinxin Wang Zhiqiang Zhang Jiang Deng Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu 610213 China Key Laboratory of the Ministry of Education on Smart Power Grids (Tianjin University) Tianjin 300072 China

Data centers have the characteristics of huge energy consumption and strong power fluctuations. To solve the problem of unstable supply and demand such as frequent power fluctuations in the micro-grid of the data center using renewable energies, this paper establishes a controllable load model of server clusters based on the task migration mechanism by analyzing the various tasks and characteristics of large cloud data centers, as well as edge computing nodes. Through the collaborative optimization control of edge and cloud computing tasks, and dynamically adjusting and migrating the server cluster load, a new data center tie-line power control method is proposed. The results of calculation examples show that the method can achieve power smoothing of large-scale cloud data center tie lines through cloud-edge collaborative control.

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Reduced-order modelling and quantifying local entropy production with triple decomposition in a low-pressure turbine

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Thermal science and Engineering Progress 2025年 63卷

作者： Bihai He Chenxing Hu Hao Liu Shufan Wu School of Aeronautics and Astronautics Shanghai Jiao Tong University Shanghai 200240 China National Key Laboratory of Science and Technology on Multi-perch Vehicle Driving Systems Beijing Institute of Technology Beijing 100081 China Tangshan Research Institute Beijing Institute of Technology Tangshan Hebei 063000 China Shanghai Aircraft Design & Research Institute Commercial Aircraft Corporation of China Shanghai 201210 China

The precise quantification of energy losses induced by multiscale flow structures in turbomachinery remains challenging, particularly under periodic wake disturbances. One of the bottleneck problems, which is frequently encountered in critical conditions for turbomachinery, lies at recognizing the losses associated with the large-scale perturbations or coherent structures in turbulent flows. This study addresses the critical need to distinguish irreversible losses from large-scale coherent structures versus random turbulence in a low-pressure turbine. A framework integrating triple decomposition of entropy production with quadruple Proper Orthogonal Decomposition was developed, enabling spatiotemporal separation of mean flow, wake-driven coherent motions, and small-scale turbulence. In order to validate the ability of the method in quantifying the irreversibility of wake flows, a low-pressure turbine cascade with incoming periodic wakes was numerically analyzed with simulations. For what concerns the quantitative estimation of the entropy production by mean flow, coherent flow and random turbulent flow are obtained. The entropy production by mean flow accounts for almost 99% of the total energy. The main energy loss induced by the coherent structure are found near 90% axial length and suction side of blade, driven by the tip leakage vortex and passage vortex. The energy loss induced by small-scale turbulent flow is similar with that of coherent structure, except from a more significant impact by the incoming wakes at 30% axial length of blade downstream leading edge. The methodology advances conventional Reynolds-averaged entropy analysis by resolving scale-specific loss mechanisms, and establishes a paradigm for optimizing turbine designs against multiscale flow irreversibility.

关键词： Large-scale perturbations Local entropy production Low-pressure turbine Proper orthogonal decomposition Triple decomposition

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Emergence of nodal-knot transitions by disorder

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science Bulletin 2025年

作者： Gong, Ming Zhao, Peng-Lu Lu, Hai-Zhou Niu, Qian Xie, X.C. International Center for Quantum Materials School of Physics Peking University Beijing100871 China Department of Physics University of Science and Technology of China Hefei230026 China Shenzhen518055 China Shenzhen518045 China CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics University of Science and Technology of China Hefei230026 China International Center for Quantum Design of Functional Materials University of Science and Technology of China Hefei230026 China Institute for Nanoelectronic Devices and Quantum Computing Fudan University Shanghai200433 China Hefei National Laboratory Hefei230088 China

Under certain symmetries, degenerate points in three-dimensional metals form one-dimensional nodal lines. These nodal lines sometimes exhibit intricate knotted structures and have been studied in various contexts. As one of the most common physical perturbations, disorder effects often trigger novel quantum phase transitions. For nodal-knot phases, whether disorder can drive knot transitions remains an open and intriguing question. Employing renormalization-group calculations, we demonstrate that nodal-knot transitions emerge in the presence of weak disorder. Specifically, both chemical-potential-type and magnetic-type disorders can induce knot transitions, resulting in the emergence of distinct knot topologies. The transition can be quantitatively characterized by changes in topological invariants such as the knot Wilson loop integrals. Our findings open up a new avenue for manipulating the topology of nodal-knot phases through disorder effects. © 2025 science China Press

关键词： Disorder Nodal-knot Renormalization group Topological phase transition

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Electronic, adsorption, and hydration structures of water-contained Na-montmorillonite and Na-beidellite through the first-principles method combined with the classical solution theory

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Physical Review Materials 2022年第2期6卷 025001-025001页

作者： Satoshi Hagiwara Yasunobu Ando Yuta Goto Susumu Shinoki Minoru Otani Center for Computational Sciences University of Tsukuba 1-1-1 Tenno-dai Tsukuba Ibaraki 305-8577 Japan Research Center for Computational Design of Advanced Functional Materials (CD-FMat) National Institute of Advanced Industrial Science and Technology (AIST) 1-1-1 Umezono Tsukuba Ibaraki 305-8568 Japan Iwaki Laboratory Kunimine Industries Co. Ltd. 23-5 Kuidesaku Jobanshimofunao-machi Iwakishi Fukushima 972-8312 Japan

We investigated the electronic and hydration structures of montmorillonite (MMT) and beidellite (BEI) using a first-principles method combined with classical solution theory. Both MMT and BEI belong to a family of clay minerals with a layered structure containing water molecules and cations in the interlayer. First, we optimized the number of accumulated water molecules in the interlayer space and found the present results to be in reasonable agreement with previous experiments. Next, we refined the positions of the cations to determine the most stable structure based on the adsorption energy of the clay layers. We found that the cations in the interlayer stably adsorb to the clay layers and the most stable adsorption site is the center of the six-membered ring. The hydration structure strongly depends on the cation adsorption structure based on the charge density distribution of the water. In contrast, the electronic state is weakly dependent on the adsorption structure because of its insulating electronic structure. Therefore, our results strongly suggest that the physical properties of MMT and BEI arise from changes in the hydration structure induced by cation adsorption/desorption.

关键词： Charge Electronic structure Electrostatic interactions Van der Waals interaction Clay gels Liquid-solid interfaces Density functional theory

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Molecular Mechanisms Underlying the Establishment, Maintenance, and Removal of DNA Methylation in Plants

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Annual review of plant biology 2025年第1期76卷 2025 Mar 3页

作者： Guohui Xie Xuan Du Hongmiao Hu Jiamu Du 1Shenzhen Key Laboratory of Plant Genetic Engineering and Molecular Design Institute of Plant and Food Science Department of Biology School of Life Sciences Southern University of Science and Technology Shenzhen China email: dujm@***. 2Guangdong Provincial Key Laboratory for Plant Epigenetics College of Life Sciences and Oceanography Shenzhen China. 3MRC Laboratory of Molecular Biology Cambridge United Kingdom. 4Institute for Biological Electron Microscopy Southern University of Science and Technology Shenzhen China.

Methylation at the fifth position of the cytosine base (5mC) is a critical DNA modification with important functions in gene silencing, genome imprinting, and suppression of transposable elements in eukaryotes. Biochemically, DNA methylation is dynamically regulated by three critical processes: the de novo establishment of DNA methylation, the maintenance of DNA methylation by preexisting methylation patterns, and the removal of DNA methylation. In plants, DNA methylation is very complex with unique features. In past decades, a series of biochemical and structural studies, especially empowered by the recent breakthroughs of high-resolution cryogenic electron microscopy, have helped uncover the molecular mechanisms underlying the establishment, maintenance, and removal of DNA methylation in plants. This review summarizes recent research advances in these three aspects of DNA methylation and lays out a molecular view of plant DNA methylation from biochemical and structural perspectives.

关键词： DNA demethylation epigenetic regulation histone modification long noncoding RNA RNA-directed DNA methylation small interfering RNA

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